Exhaust

[Gnasher]

I recomend Delkevic. Their products are tested for every bike on the Dyno, so they are build specificaly for the bike

All decent cans are built the same way  Unless you go full race system most end cans do little other than make a bit more noise or a different sound couple bhp at most.  This is especially poignant with FZS1000s as performance is governed to a large extent by std fuelling and the EXUP. 

Even with full jet kit e.g. Ivans, AIS and air box mod etc you'll get around 10bhp.  What the latter does is clean up the low and mid range giving a lot better spread of usable power and you don't need to fit an end can to get most of the gain.  End cans are really just about noise and looks, most bikes in the last 10yrs ish, the std exhaust system is as good as you're going to get, fitting end cans without proper remaps or emission control removal e.g. air boost, CAT's etc will decrease power in some cases significantly.  Noise doesn't equal power